Fix for PMI assert: 'vnWx != NoVN'

Commit migrated from https://github.com/dotnet/coreclr/commit/d80bbeebc88117f3c2e696a1f4fcfeb844c02557

diff --git a/src/coreclr/src/jit/valuenum.cpp b/src/coreclr/src/jit/valuenum.cpp
index 852cd65..0ea6df9 100644 (file)
--- a/src/coreclr/src/jit/valuenum.cpp
+++ b/src/coreclr/src/jit/valuenum.cpp
@@ -6777,29 +6777,33 @@ void Compiler::fgValueNumberBlockAssignment(GenTree* tree)
                     JITDUMP("    *** Missing field sequence info for Dst/LHS of COPYBLK\n");
                     isNewUniq = true;
                 }
-                else if (lhsFldSeq != nullptr && isEntire)
-                {
-                    // This can occur for structs with one field, itself of a struct type.
-                    // We are assigning the one field and it is also the entire enclosing struct.
-                    //
-                    // Use an unique value number for the old map, as this is an an entire assignment
-                    // and we won't have any other values in the map
-                    ValueNumPair oldMap;
-                    oldMap.SetBoth(vnStore->VNForExpr(compCurBB, lclVarTree->TypeGet()));
-                    rhsVNPair = vnStore->VNPairApplySelectorsAssign(oldMap, lhsFldSeq, rhsVNPair, lclVarTree->TypeGet(),
-                                                                    compCurBB);
-                }
-                else if (!isNewUniq)
-                {
-                    ValueNumPair oldLhsVNPair = lvaTable[lhsLclNum].GetPerSsaData(lclVarTree->GetSsaNum())->m_vnPair;
-                    rhsVNPair                 = vnStore->VNPairApplySelectorsAssign(oldLhsVNPair, lhsFldSeq, rhsVNPair,
-                                                                    lclVarTree->TypeGet(), compCurBB);
-                }
 
                 if (isNewUniq)
                 {
                     rhsVNPair.SetBoth(vnStore->VNForExpr(compCurBB, lclVarTree->TypeGet()));
                 }
+                else // We will assign rhsVNPair into a map[lhsFldSeq]
+                {
+                    if (lhsFldSeq != nullptr && isEntire)
+                    {
+                        // This can occur for structs with one field, itself of a struct type.
+                        // We are assigning the one field and it is also the entire enclosing struct.
+                        //
+                        // Use an unique value number for the old map, as this is an an entire assignment
+                        // and we won't have any other values in the map
+                        ValueNumPair uniqueMap;
+                        uniqueMap.SetBoth(vnStore->VNForExpr(compCurBB, lclVarTree->TypeGet()));
+                        rhsVNPair = vnStore->VNPairApplySelectorsAssign(uniqueMap, lhsFldSeq, rhsVNPair,
+                                                                        lclVarTree->TypeGet(), compCurBB);
+                    }
+                    else
+                    {
+                        ValueNumPair oldLhsVNPair =
+                            lvaTable[lhsLclNum].GetPerSsaData(lclVarTree->GetSsaNum())->m_vnPair;
+                        rhsVNPair = vnStore->VNPairApplySelectorsAssign(oldLhsVNPair, lhsFldSeq, rhsVNPair,
+                                                                        lclVarTree->TypeGet(), compCurBB);
+                    }
+                }
 
                 lvaTable[lhsLclNum].GetPerSsaData(lclDefSsaNum)->m_vnPair = vnStore->VNPNormalPair(rhsVNPair);
 
@@ -6883,7 +6887,6 @@ void Compiler::fgValueNumberTree(GenTree* tree)
         switch (oper)
         {
             case GT_LCL_VAR:
-            case GT_REG_VAR:
             {
                 GenTreeLclVarCommon* lcl    = tree->AsLclVarCommon();
                 unsigned             lclNum = lcl->gtLclNum;
@@ -7252,7 +7255,6 @@ void Compiler::fgValueNumberTree(GenTree* tree)
             switch (lhs->OperGet())
             {
                 case GT_LCL_VAR:
-                case GT_REG_VAR:
                 {
                     GenTreeLclVarCommon* lcl          = lhs->AsLclVarCommon();
                     unsigned             lclDefSsaNum = GetSsaNumForLocalVarDef(lcl);